Storage migration from Google Cloud Storage to Azure with Async/Await

project.json

{
  "frameworks": {
    "net46":{
      "dependencies": {
          "Google.Cloud.Storage.V1": "1.0.0-beta05"
      }
    }
  }
}

run.csx

#r "Microsoft.WindowsAzure.Storage"
using System;
using System.IO;
using Google.Cloud.Storage.V1;
using Microsoft.WindowsAzure.Storage;
using Google.Apis.Auth.OAuth2;

public async static Task Run(string message, TraceWriter log)
{
    log.Info($"C# Queue trigger function processed: {message}");
    // Environment.SetEnvironmentVariable("GOOGLE_APPLICATION_CREDENTIALS", "D:\\home\\site\\wwwroot\\{YOUR FUNCTION NAME}\\servicecert.json"); // this function is from 1.0.0-beta06
    
    // Google Storage
    var credential = GoogleCredential.FromStream(System.IO.File.OpenRead("D:\\home\\site\\wwwroot\\{YOUR FUNCTION NAME}\\servicecert.json"));
    var client = StorageClient.Create(credential);
    var bucketName = "simpleatest";

    // Azure Storage Account 
    var storageAccount = CloudStorageAccount.Parse("BlobEndpoint={YOUR BLOB SERVICE SAS TOKEN is here}");
    var blobClient = storageAccount.CreateCloudBlobClient();
    var container = blobClient.GetContainerReference(bucketName);
    await container.CreateIfNotExistsAsync();

    foreach(var obj in client.ListObjects(bucketName, message))
    {
        if (IsDirectory(obj.Name))
        {
            container.GetDirectoryReference(obj.Name);
        } else 
        {
            var blockBlob = container.GetBlockBlobReference(obj.Name);
            using (var stream = await blockBlob.OpenWriteAsync())
            {
                await client.DownloadObjectAsync(bucketName, obj.Name, stream);
            }
        }
    log.Info($"{obj.Name}:{obj.ContentType}");        
    }
}

private static bool IsDirectory(string backetPath)
{
    return backetPath.EndsWith("/");
}

Edit {YOUR FUNCTION NAME} and {YOUR BLOB SERVICE SAS TOKEN is here}
Example
{YOUR FUNCTION NAME} : GCSMigration
{YOUR BLOB SERVICE SAS TOKEN is here}: https://xxxxx.blob.core.windows.net/?sv=2015-12-11&ss=bfqt&srt=sco&sp=rwdlacup&se=2017-01-03T02:47:40Z&st=2016-12-31T18:47:40Z&spr=https&sig=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

You can refer this blog post
https://blogs.technet.microsoft.com/livedevopsinjapan/2017/01/02/storage-migration-from-google-cloud-to-azure-using-azure-functions/